Mudanças Climáticas Globais ea - · PDF file Mudanças climáticas...

Click here to load reader

  • date post

    08-Oct-2020
  • Category

    Documents

  • view

    0
  • download

    0

Embed Size (px)

Transcript of Mudanças Climáticas Globais ea - · PDF file Mudanças climáticas...

  • Empresa Brasileira de Pesquisa Agropecuária Embrapa Hortaliças

    Ministério da Agricultura, Pecuária e Abastecimento

    Mudanças Climáticas Globais e a Produção de Hortaliças

    Ítalo Moraes Rocha Guedes Editor Técnico

    Brasilia, DF

    2009

  • Exemplares desta publicação podem ser adquiridos na:

    Embrapa Hortaliças BR 060, Rodovia Brasília-Anápolis, Km 09 Caixa Postal 218, 70359-970, Brasilia, DF Fone: (61) 3385-9009 Fax: (61) 3556-5744 [email protected] www.cnph.embrapa.br

    Comitê de Publicações da Embrapa Hortaliças Presidente: Warley Marcos Nascimento Editora-Técnica: Mirtes Freitas Lima Membros: Jadir Borges Pinheiro, Miguel Michereff Filho, Milza Moreira Lana, Ronessa Bartolomeu de Souza

    Normalização bibliográfica Rosane Mendes Parmagnani

    1a edição 1a impressão (2009): 500 exemplares

    Todos os direitos reservados. A reprodução não-autorizada desta publicação, no todo ou em parte, constitui violação dos direitos autorais (Lei nO9.610).

    Dados Internacionais de Catalogação na Publicação (CIP) Embrapa Hortaliças

    Guedes, Italo Moraes Rocha

    Mudanças climáticas globais e a produção de hortaliças I [talo Moraes Rocha Guedes, editor técnico. - Brasflia : Embrapa Hortaliças, 2009.

    132 p.

    ISBN 978-85-86413-17-9

    1. Hortaliça - Produção - Clima. I. Título.

    CDD 635.0469 ©Embrapa, 2009

    Comissão Organizadora do Evento: Carla Timm

    Celso Luiz Moretti .

    Jairo Vidal Vieira

    WarleyMarcos Nascimento

    Coordenador: Ítalo Moraes Rocha Guedes

    Realização: Embrapa Hortaliças

    Patrocinadora do Workshop "Efeitos das Mudanças Climáticas na Produção de Hortaliças", realizado em 20 de novembro de 2009:

    Fundação de Apoio à Pesquisa do Distrito Federal- FAPDF

    mailto:[email protected] http://www.cnph.embrapa.br

  • LOPES, C. A.; AVILA, A. C. Doenças do tomateiro. Brasilia, DF: Embraps Hortaliças, 2005. 151 p.

    MINAM!, K.; HAAG, H. P. O tomateiro. Piracicaba: Fundação Cargil, 2005. 397 P.

    REIS, A.; DIAS, R. c,ARAGÃO, F.A. S.; BOITEUX, L. S. Caracterização do perfil patogênico de isolados de Podosphaera xanthii em cucurbitáceas na região nordeste do Brasil. Horticultura Brasileira, Brasilia, DF, v. 23, p. 362, 2005. Suplemento.

    VALE, F. X. R.; ZAMBOLIM, L.; PAUL, P. A.; COSTA, H. Doenças causadas por fungos em tomate. In: ZAMBOLIM, L.; VALE, F. X. R.; COSTA, H. Controle de doenças de plantas hortaliças. Viçosa, MG: Universidade Federal de Viçosa, 2000. v. 2, p. 699-756.

    64

    CAPÍTULO V

    Potential impacts of climate changes on the quality of fruits and vegetables

    C. L. Moretti', L. M. Mattos', A.G. Calbo", S.A. Sargenr' I Embrapa Vegetables, 2 Embrapa Agricultural Instrumentation, 3 Horticultural Sciences

    Department, University of Florida, Gainesville

    Introduction

    Climate on Earth has changed many times during the existence of our planet, ranging from the ice ages to periods of warmth. During the last several decades increases in average air temperatures have been reported and associated effects on climate have· been debated worldwide in a variety of forums. Due to its importance around the globe, agriculture was one of the first sectors to be studied in terms of potencial impacts of climate change (ADAMS et al., 1990). Many alternacives have been proposed to growers aimed at minimizing losses in yield. However, few studies have addressed changes in postharvest quality of fruits and vegetable crops associated with these alterations, Nowadays, climate changes, their causes and consequences, gained importance in many other areas of interest for sustainable life on Earth. The subject is, however, controversial.

    According to studies carried out by the Intergovernrnental Panel on Climate Change (Ipcq, average air temperatures will increase between 1.4 and 5.80 C by the end of this century, based upon modeling techniques that incorporated data from ocean and atmospheric behavior (IPCC, 2001). The possible impacts of this study, however, are uncertain since processes such as heat, carbon, and radiation exchange among different ecosystems are still under invescigation. Less drastic estimates predict temperature increase rates of 0.0880 C per decade for this century (KALNAY; CAI, 2003). Other, investigators forecast for the near future that rising air temperature could induce more frequent occurrence of extreme drought, fiooding or heat waves than in the past (ASSAD et al., 2004).

    Higher temperatures can increase the capacity of air to absorb water vapor and, consequently, generate a higher demand for water, Higher

    65

  • evapotranspiration indices could lower or deplete the water reservoir in soils, creating water stress in plants during dry seasons. For example, water stress is of great concern in fruit production, because trees are not irrigated in man:-- production areas around the world. It is well documented that water stress not only reduces crop productivity but also tends to accelerate fruit ripening (HENSON,2008).

    Exposure to elevated temperatures can causemorphological, anatornical, physiological, and, ultimately, biochemical changes in plant tissues and, as a consequence, can affect growth and development of different plant organs. These events can cause drastic reductions in commercial yield. However, bv understanding plant tissues physiological responses to high temperatures, mechanisms of heat tolerances and possible strategies to improve yield, it is possible to predict reactions that will take place in the different steps of fruir and vegetable crops production, harvest and postharvest (KAYS, 1997).

    Besides increase in temperature and its associated effects, climate changes are also a consequence of alterations in the composition of gaseous constituents in the atrnosphere. Carbon dioxide (CO) and ozone (OJ concentrations in the atrnosphere are changing during the last decade and are affecting many aspects of fruit and vegetable crops production around the globe (FELZER et al., 2008).

    Carbon dioxide concentrations are increasing in the atrnosphere during the last decades (MEARNS, 2000). The current atrnospheric CO2 concentration is higher than at any time in the past 420,000 years (pETIT et al., 1999). Further increases due to anthropogenic activities have been predicted. Carbon dioxide concentrations are expected to be 100% higher in 2100 than the one observed at the pre-industrial era (IPCC, 2007). Ozone concentration in the atrnosphere is also increasing. Even low levels of ozone in the vicinities of big cities can cause visible injuries to plant tissues as well as physiological alterations (FELZER et al., 2007).

    The above mentioned climate changes can potentialiy cause postharvest quality alterations in fruit and vegetable crops. Although many researchers have addressed climate changes in the past and, in some cases, focused postharvest alterations, the inforrnation is not organized and available for postharvest physiologists and food scientists that are interested in better understanding how these changes will affect their area of expertise.

    In the present article we review how changes in ambient temperature and levels of carbon dioxide and ozone can potentialiy impact the postharvest quality of fruit and vegetable crops.

    66

    Harvest and postharvest

    Harvest of fruit and vegetable crops occurs in different times of the :ocardepending on cultivar, water regime, climate conditions, pest control, cultural practices, exposure to direct sunlight, temperature management and rnarurity index, among other important pre-harvest factors.

    After crops are harvested, respiration is the major pracess to be controlled. Postharvest physiologists and food scientists do not have many options to interfere with the respiratory process of harvested cornrnodities, since they are largely dependent on the product speciíic characteristics ,S}..LTVEIT,2002).

    In arder to minimize undesirable changes in quality parameters during the postharvest period, growers and entrepreneurs can adopt a series of techniques to extend the shelf life of perishable plant products. Postharvest rechnology comprises different methods of harvesting, packaging, rapid caoling, storage under refrigeration as well as modified (MA) and controlled (CA) atrnospheres and transportation under controlled conditions, among other important technologies. This set of strategies is of paramount importance to help growers ali over the world to withstand the chalienges that climate changes will impose throughout the next decades.

    Effects of temperature

    Fruit and vegetable growth and development are influenced by different environrnental factors (BINDI et al., 2001). During their development, high temperatutes can affect photosynthesis, respiration, aqueous relations and membrane stability as well as levels of plant hormones, and primary and secondary metabolites (BEWLEY, 1997).

    Most of the physiological processes go on normaliy in temperatures ranging fram 0° C to 40° C. However, cardinal temperatures for the development of fruit and vegetable crops are much narrower and, depending on the species and ecological origin, it can be pushed towards 0° C for temperate species from cold regions, such as carrots and lettuce. On the other hand, they can reach 40° C in species from tropical regions, such as mapy cucurbits and cactus species (WENT, 1953).

    A general temperature effect in plants involves the ratio between photosynthesis and respiration (WENT, 1953). High temperatures can increase the rate of biochemical reactions catalyzed by different